Memory

• Coding is the format in which information is stored in the different memory stores
• Short term memory is the temporary store of information that is held for at least 18 seconds to a few minutes. Holds 5-9 items
• Long term memory is a permanent memory store, coding mainly by meaning and it has unlimited capacity
• Capacity is the amount of information that can be held in a memory store.
• Duration is the length of time information can be held in a memory store
• Research on coding

  Baddeley (1966a, 1966b) gave different lists of words to four groups of participants to remember.

  Group 1 (acoustically similar) words sounded similar.

  Group 2 (acoustically dissimilar) words sounded different.

  Group 3 (semantically similar) words with similar meanings

  Group 4 (semantically dissimilar) words with different meanings
• Findings on research into coding

  When asked immediately, recalling from short term memory, they tended to do worst in recalling the correct order of acoustically similar words.

  When they recalled the word list after 20 mins, participants, participants did worse with the semantically similar words.
• In conclusion information coded in the STM is acoustically coded and in the LTM it is semantically coded
• +Evaluation of coding

  Identified two clear differences between memory stores

  • STM uses mostly acoustic coding
  • LTM is mainly semantic
• • Evaluation for coding

   One limitation of Baddeley’s study was that it used artificial stimuli rather than meaningful material.

  The word lists had no personal meaning to participants, so Baddeley’s findings may not tell us much about coding in different memory tasks, especially in everyday tasks
• Digit span is a measure of the amount that can be held in memory
• How was the digit spam technique looked into?

  Jacob’s conducted a laboratory study
• Digit span procedure

  Participants were given 4 digits and asked to recall them out loud in the correct order. The number of digits increased until the participant was unable to recall the order correctly. Miller suggested that the span of STM is 7 items plus or minus two.
• Jacob’s found that the mean spam for digits across all participants was 9.3 items
• the mean span for letters was 7.3 items
• Span of memory and chunking (Miller)

  Made observations of everyday practice.

  -    He noted that things come in sevens: seven notes on the musical scale, seven days of the week, seven deadly sins, etc

  -     Miller thought that the capacity of STM is about 7 items, plus or minus 2.
• But he also noted that people can recall 5 words as easily they can recall five letters.

  • We do this by chunking grouping sets of digits or letters into units or chunks
• + Evaluation- valid study

  One strength of Jacobs’ study is that it has been replicated. 

  -  The study is very old and early research often lacked adequate controls.

  Despite this his findings have been confirmed by other, better controlled studies since (Bopp and Verhaeghen 2005)
• -Evaluation on Capacity-Not so many chunks

  Nelson Cowan (2001) reviewed other research and concluded that the capacity of STM is only about 4 (plus or minus 1) chunks. Suggesting that Miller’s lower end estimate is more appropriate than seven items
• Duration is how long a memory lasts before it is no longer available
• Duration of STM

  Information in STM lasts only a short time unless it’s rehearsed.
• Duration study- Peterson and Peterson

  Tested 24 students in eight trials (test)

  • On each trial students were given a consonant syllable pr 3 digit number to remember and repeat in order after a 3, 6 ,9, 12, 15 or 18s delay
  • Particpants were given an interference task to prevent any ,mental rehearsal
• Peterson and Peterson found that if participants were asked to repeat the numbers every three seconds then their duration was around 39 minutes. However, when they weren't allowed to rehearse, their duration dropped to just over two minutes.
• Duration study- findings

  After 3s recall was about 80%

  After 18 seconds it was about 3% unless the information was repeated
• Duration of LTM

  Bahrick concluded that people could remember certain types of information, such as names and faces for almost a lifetime.
• How was recall tested in Bahrick's study:

  1.       Free recall- remembering names of classmates.

  2.       Visual recognition- recognising photographs.

  3.       Verbal recognition- recognising names.
• Free recall task60% accuracy if graduated within 15 years.

  • 30% accuracy if graduated within 48 years
• Free recall task-

  • 60% accuracy if graduated within 15 years.
  • 30% accuracy if graduated within 48 years
• The multi store model is representation of how memory works in terms of three stores called: sensory register, short term memory, long term memory
• The multi store model descibes how information is transferred from one store to another and what makes one memory last or disappear
• Sensory register is the memory store of our five senses like vision (iconic stores) and hearing (echoic)
• Echoic store is where sounds are stored for up to four seconds
• Atkinson and Shiffrin's multi store model describes how information flows through the memory system, three stores are linked by processing
• Multi Store Model

  
• Information passes further into the memory system only if you pay attention to it.

  • Meaning attention is the key process
• Short Term Memory

  • Information in short term memory is coded mainly acoustically- sound and usually lasts about 18 seconds unless it is rehearsed
• With STM only lasting 18 seconds it shows how it is a temporary store
• The capacity of STM is around five items of information according to Cowan’s research- Limited Capacity
• Maintenance rehearsal


  When we rehearse information/material to ourselves repeatedly

  • If we keep rehearsing it can remain in our STM and then move to LTM
• Long Term Memory


  Potentially more permanent memory store for information that has been rehearsed for a long period of time